Grating for coaling stations



Feb. 24, 1942. A. B. CHAPMAN 2,274,397

GRATING FOR ICOALING STATIONS Filed March 30, 1940 INVENTOR.

50, (WU Lari,

BY M %@u ATTORNEYS.

Patented Feb. 24, 1942 UNITED STATES PATENT OFFICE 2,274,397 GRATING FOR. COALING STATIONS Asa B. Chapman, Evanston, Ill. Application March 30, 1940, SerialNo. 327,022

7 Claims.

Lumps of coal used for firing locomotives should not exceed a certain size. The coaling stations are equipped with suitable means for reducing lumps that are too large and insuring that no such lumps reach the delivery chute.

One such means is a grating of stout bars guarding the top of the coal hopper and upon which lumps that are. too large are caughtand held until broken with hammers. I p

Such gratings have been made of 5 x fiat bars held in spaced relation by crosswiseflat bars of the same size connected to the first mentioned bars by half-lap joints or by being cut into to greatly weaken them) and welding each rod to each of those bars tohold the bars'firmly in place notwithstanding the heavy blows they receive in service when carloads of coal are dumped on the grating and when large lumps supported on the bars and sometimes wedged between the bars are struck breaking blows.

Additional objects and advantages'of the invention will be apparent from the following description and from the drawing, in which:

Fig. 1 is a fragmentary transverse sectional view of the pit of a coaling station, showing cross sections of a plurality of gratings chosen for illustration of the present invention.

Fig. 2 is a plan view of a grating assembly used in Fig. 1.

Fig. 3 is an enlarged fragmentary plan view of the gratings illustrated in Figs. 1 and-2.

Fig. 4 is a fragmentary end view taken approximately on the line 4-4 of Fig. 3.

Fig. 5 is a fragmentary longitudinal sectional View taken approximately on the line 5-5 of Fig. 3.

A preferred form of the invention has been chosen for illustration and description, in compliance with Section 4888 of the Revised Statutes, but persons skilled in the art will readily perceive other means utilizing the invention for accomplishing the same or' similar results.

The invention has been illustrated in connection with a coaling station or the like having pit walls H, at least one of which is preferably inclined to form a hopper leading to a delivery chute. A track comprising rails l2 extends over the pit so that carloads of coal may be drawn over the pit and dumped onto the screens or gratings l3. Gratings are also called breaker bars because of the fact that in coaling stations when lumps of coal are too large to go through the grating, a hammer is used for breaking up the lumps retained by the bars. Another common term for such a grating is grizzly.

The rails I2 are conventionally supported by track girders M which also aid in supporting the grating-s l3. Thus, as seen clearly in Fig. 1, the side gratings are supported between one girder l4 and a side wall H, and the centergrating is supported between the two girders l4.

Because of the weight of the coal and even more because of the forces applied to the coal. in striking it with a hammer to break the coal, the requirements for the gratings are quite rigid. Obviously the grating must have sufficient beam strength to withstand the vertical load and the vertical force of the hammer. In addition, the grating must be so constructed that the individual bars will not flex much in a lateral direction since, if they did so, the force of a hammer would simply push the large lumps of coal through without breaking the coal. Gratings have been made in a number of different ways to provide the necessary strength. Flat bars extending in both directions with half-lap joints 'or with the bars in one direction cut into lengths costly. Furthermore, if half-lap joints were used,

the beam strength of the memberswas greatly reduced unless welding was resorted to in addition.

According to the present invention the gratings are made up of flat parallel bars l6 extending in one direction, and connecting rods I! extending through holes in the bars and welded to each bar to prevent flexing of the bars. The grating is disposed with its fiat bars extending between the supporting members, as seen in Fig. 1, so that the beam strength of these members is fully utilized. Since the rods H are supported by the bars l6, it is not necessary for the rods to have any great beam strength. The effective span or beam length for these rods is only the distance between the bars 16. Maximum beam strength is obtained from the'flat bars 16, on the other hand, since the holes for the rods H are in intermediate portions of the bars, leaving intact the marginal portions of the bar which serve as the main compressional and tensional members of the beam. It has been found, for example, that 4" bars in gratings of the present construction can be used in instances where 5" bars have been used in prior grating constructions which did not make full use of the strength of the metal.

Although a single weld between each rod and each bar would be sufficiently strong to prevent spreading of the bars by forces applied immediately adjacent the welds, it is evident that forces applied to the top edges of the bars, as by a lump of coal 19 in Fig. 5, would exert not only a spreading force but a twisting force on the bars, tending to twist the bars about eachweld as the fulcrum. This would of course tend to break the weld and in turn permit spreading of the bars. Positioning the rods a substantial distance below the tops of the bars makes it impossible to weld in the top plane and hence sulficient strength must be provided in some way to prevent twisting of the bars with the leverage between the top edge of the bar and, the rod. As best seen in Fig. 5, this is accomplished by welding each rod to each bar at two points which are diagonally disposed in a vertical plane. Thus, one weld 2i will be positioned at the top of rod l1 and on the left-hand side of bar 16, while the other weld 22 will be at the bottom of rod I! and on the right-hand side of bar It. This gives the maximum possible spacing of the welds securing any thickness of bar to a given diameter of rod. Of course, having welds at the top and bottom of the rods, even on the same side of a bar, would be far superior to single Welds or two Welds confined to the vertical center of the rods.

By positioning the rods H as near to the top of the bars as is consistent with maintaining the beamstrength of the bars, leverage between the top edges and the welds is kept at a minimum. Furthermore, this positioning minimizes the tendency of slightly oversize lumps to stick near the bottom of the grating where it is relatively hard to hit them with a hammer to knock them out.

Although dimensions will of course be varied according to circumstances,- a grating has been found to be satisfactory using i" X bars and ,1" rods extending through 1%" holes centered .1 from the top edge of the bars. which are called tack welds, have been found to The welds, U

be sufiicient if each extends /2" along the pe riphery of the rod and l e" longitudinally of the rod and the bars. A grating of this form having 7" x 7 clear openings weighs only approximately l'lpounds per square foot of grating area. It will be observed that with these dimensions two cooperating diagonally positioned welds are as far apart as the length of the leverage arm between the top edge of a bar and the nearest weld. The gratings are preferably provided with stops 23 welded to the end bars of each section to retain the grating properly positioned between the support members. These stops may project two inches below the bottom of the bars I6 and may be 2" X x 3" bars.

In using a series of gratings, as seen in Fig. 2, adjacent gratings are preferably arranged with the rods l staggered with respect to one another so that each rod may project through the end out requiring the endbars to be spaced far apart.

With the end bars close together, as seen at 2-6 in Fig. 2, very few large lumps of coal will fall between the end bars and hence there will be ,very little force *tending to spread the gratings apart. Accordingly, if the end gratings of each series are anchored, it will not be necessary to secure the gratings together. Obviously they may be secured together in any desired manner, however. In order to have the rods I! of two adjacent gratings staggered with respect to one another, it is not necessary to have two different gratings as illustrated here. By slightly changing the spacing of the rods or slightly shortening the length of the bars, each grating could be made unsymmetrical, with the bar at one end closer to the end than is the bar at the other end. It would then merely be necessary to have adjacent gratings oppositely disposed in order to stagger the rods of one grating with respect to those of the adjacent grating.

From the foregoing it is seen that gratings are provided which have adequate strength with a minimum of metal and which are of such form that they may be very economically constructed, requiring only simple punching, assembling and welding operations. Although the gratings are designed especially for the rigid requirements of a coaling station, they may of course be used for numerous other purposes.

I claim:

.1. In a breaker bar grating, a plurality of flat support bars spaced apart on edge, and a plurality of spaced rods of substantially uniform cross-section passing through openings in the flat bars centered above the centers of the bars a distance at least in the order of one-eighth the depth of the bars to reduce the torque arms of the tops of the bars about the rods, and spaced substantially below the tops of the bars to retain high beam strength of the bars, each rod being welded to each fiat bar on the top of the rod and at one side only of each bar and the bottom of the rod and at the other side only of each bar whereby maximum tortional strength is provided for a given amount of welding, the rods fitting freely in the bars whereby weakening strains are avoided, the welds comprising added metal of substantial extent along the bars and along the rods longitudinally and peripherally whereby they increase the strength of the bars, and the rods being round in cross-section whereby they may withstand the blow of a maul as well at inclined and nearly horizontal directions as at a vertical direction.

2. In a breaker bar grating, a plurali y of fiat support bars spaced apart on edge, and a plurality of spaced rods of substantially uniform cross-section passing through openings in the flat bars centered above the centers of the bars a distance at least in the order of one-eighth the depth of the bars to reduce the torque arms of the tops of the bars about the rods, and spaced substantially below the tops of the bars to retain high beam strength of the bars, each rod being welded to each flat bar on the top of the rod and at one side only of each bar and the bottom of the rod and at the other side only of each bar whereby maximum tortional strength is provided for a given amount of welding, the welds comprising added metal of substantial eX- tent along the bars and along the rods longitudinally and peripherally whereby they increase the strength of the bars, and the rods being round in cross-section whereby they may withstand the blow of a maul as well at inclined and nearly horizontal directions as at a vertical direction.

3. In a breaker bar grating, a plurality of fiat support bars spaced apart on edge, and a plurality of spaced rods of substantially uniform crosssection passing through openings in the flat bars centered above the centers of the bars a distance at least in the order of one-eighth the depth of the bars to reduce the torque arms of the tops of the bars about the rods, and spaced substantially below the tops of the bars to retain high beam strength of thebars, each rod being welded to each flat bar on the top of the rod and at one side only of each bar and the bottom of the rod and at the other side only of each bar whereby maximum tortional strength is provided for a given amount of welding, and the welds comprising added metal of substantial extent along the bars and along the rods longitudinally and peripherally whereby they increase the strength of the bars.

4. In a breaker bar grating, a plurality of flat support bars spaced apart on edge, and a plurality of spaced rods of substantially uniform flat bars centered above the centers of the bars I a distance at least in the order of one-eighth the depth of the bars to reduce the torque arms of the tops of the bars about the rods, and spaced substantially below the tops of the bars to retain high beam strength of the bars, each rod being welded to each flat bar on the top of the rod and at one side only of each bar and the bottom of the rod and at one side only of each bar whereby approximately maximum tortional strength is provided for a given amount of welding, the welds comprising added metal of substantial extent along the bars and along the rods longitudinally and peripherally whereby they increase the strength of the bars, and the rods being round in cross-section whereby they may withstand the blow of a maul as well at inclined and nearly horizontal directions as at a vertical direction.

5. In a breaker bar grating, a plurality of flat support bars spaced apart on edge, and a plurality of spaced rods of substantially uniform cross-section passing through openings in the flat bars centered above the centers of the bars a distance at least in the order of one-eighth the depth of the bars to reduce the torque arms of the tops of the bars about the rods, and spaced substantially below the tops of the bars to retain high beam strength of the bars, each rod being welded to each fiat bar on the top of the rod and at one side only of each bar and the botcrease the strength of the bars, the rods being of substantially the same transverse dimensions horizontally and vertically.

6. In a breaker bar grating, a plurality of flat support bars spaced apart on edge, and a plurality of spaced rods of substantially uniform cross-section passing through openings in the flat bars centered closer to the centers of the bars than the tops of the bars but above the centers of the bars a distance at least in the order of one-eighth the depth of the bars to reduce the torque arms of the tops of the bars about the rods, and spaced substantially below the tops of the bars to retain high beam strength of the bars, each rod being welded to each flat bar on the top of'the rod and at one side only of each bar and the bottom of the rod and at one side only of each bar whereby approximately maximum tortional strength is provided for a given amount of welding, and the welds comprising added metal of substantial extent along the bars and along the rods longitudinally and peripherally whereby they increase the strength of the bars.

'7. In a breaker bar grating, a plurality of flat support bars of uniform thickness spaced apart on edge, and a plurality of spaced rods of substantially uniform cross-section passing through openings in the fiat bars centered closer to the centers of the bars than the tops of the bars but above the centers of the bars a distance at least in the order of one-eighth the depth of the bars to reduce the torque arms of the tops of the bars about the rods, and spaced substantially below the tops of the barsto retain high beam strength of the bars, each rod being welded to each flat bar on the top of the rod and at one side of each bar and the bottom of the rod at the other side of each bar whereby maximum tortional strength is provided for a given amount of welding, the rods fitting freely in the bars whereby weakening strains are avoided, the welds comprising added metal of substantial extent along the bars and along the rods longitudinally and peripherally whereby they increase the strength of the bars, the rods being of substantially the same transverse dimensions horizontally and vertically.

ASA B. CHAPMAN. 

